Furnace-grate.



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No. 667,399. Patented Feb. 5, Ism.. F. r. MAIER.

FURNACE SKATE.

(Application led Aug. 23, 1897.

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. HAI" No. 567,399. Patented Feb. 5, fsm. F. F. MAIER. FURNACE GRATE.

(tppliction led Aug. 23. 1897.i

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"w- I u UNT'TED STATES PATENT OFFICE.

FRITZ FRANZ MAIER, OF VIENNA, AUSTRIA-HUNGARY, ASSIGNOR OF ONE- HALF TOSIGMUND KANITZ, OF SAME PLACE.

FU RNACE-G RATE.

SPECIFICATION' forming part of Letters Patent No. 667,399, datedFebruary 5, 1901.

Application filed August 23, 1897, Serial No. 649,271. (No model.)

T all whom it may concern:

Be it known that I, FRITZ FRANZ MAIER, a subject of the Emperor ofAustria-Hungary, residing at Vienna, in the Province of Lower Austria,in the Empire of Austria-Hungary,

have invented certain new and useful Improvements in Furnace-Gratos,(for which Letters Patent have been obtained in Austria, dated May 28,1897, registered Vol. 47, Fol.

1o 1986;) and I do hereby declare the following to be a full, clear, andexact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same, referencebeing had to the accompanying drawings, and to letters of referencemarked thereon, which form a part ofY this specification.

This invention relates to improvements in that type of furnace in whichthe feeding for- :zo ward of the fuel, the clearing of the fire-grate,

and the removal of clinkers and ashes therefrom are ei'ected by means ofa movable sliding grate in conjunction with a fixed stepgrate providedwith cooling means. These furnaces have many and serious defects whichinterfere with their good Working and which form disturbing elementsgenerally. The defects consist, mainly, in that the fixed stepgrate barsare so constructed that all the grate- 3o openings are closed by therising of the sliding grate, and thus prevent the entry of air,

that the cooling-passages are too far removed from the surfaces to becooled, and thus through the unfavorable circulation of the' coolingmedium cause a defective system of cooling. Further, in consequence ofthe great quantity of material required in the construction of the partsof these furnaces such construction is rendered difficult, while at the4o same time the total area of the openings of the fire-grate isdisadvantageously reduced,

and the increased heat-conducting surface greatly interferes with theair-currents passing through the open spaces of the grate.

The improvements for obviating the above defects and for rendering suchfurnaces really smokeless must therefore aim (d) at an arrangement ofthe step-grate and its supporting-frame relatively to the sliding grate,in 5o which the air-passages between the bars of the step-grate possessin any position of the sliding grate a relatively larger cross-sectionalarea, (b) at rendering the action of the cooling medium in the framemost effective, and (c) at arranging the cooling-passages in thestep-grate as near as possible to the surface of combustion.

Improvements have also been introduced in the device for moving thesliding grate, in the feeding device, and in the means for ob- 6otaining a uniform combustion of the fuel throughout the entire Width ofthe fire-grate, and, iinally, for enabling the parts of both the stepand the sliding grates to be easily removed and exchanged.

The accompanying drawings illustrate several furnaces provided With theabove improvements.

Figure 1 is a vertical longitudinal section of a furnace constructedaccording to this 7o invention and provided with the improved chargingdevice. Fig. 1a is a modification of the charging device. Fig. 2 is aplan of the furnace. Fig. 3 is a side elevation of the grate, and Figs.4t and 5 are two cross-sections 75 taken on different vertical planes.Fig. 6 is a vertical longitudinal section of a modified construction offurnace. Fig. 7 is a vertical cross-section of the same. Figs. 8 and 9represent one of the sliding bars of the movable 8o grate in twoexternal views and in two crosssectious. Figs. 10 and 11 show alongitudinal and a cross section, respectively, of a furnace built ofbricks or masonry.

a, are the hollow bars of the fixed or step grate.

b are the sliding bars of the movable grate, which are arranged betweenthe former in such a manner as to effect at one and the same time thefeeding forward of the fuel as 9o Well as the clearing of the grate andthe removal therefrom of the ashes and clinkers.

The main support of the fire-grate possesses the form of a frame havingin both its longitudinal branches A passages serving as inlet and outletto the cooling medium, Which latter may be Water, air, or air mixed withatomized Water. These two longitudinal branches are connected togetherby the hollow stepbars a.. The latter are provided with ribs a roo andwith an asbestos packing-ring at each end and are secured to thebranches A in such manner as to enable each single bar to be taken outlwhen required for renewal without having to take the Whole grate out oleven without having to dismount any other parts whatever.

The hollow step-bars a are of comparatively small cross-section, so asto leave large openings between them for the passage of air from theash-pit for combustion. Further, these bars are arranged parallel withthe bars or slides b of the 'movable grate and so that said slides, evenin their most outward position, only reach with their recessed portionsVinto the spaces between the hollow bars, and thus never block out theair. This arrangement enables the section of the iron in the grate to bereduced to a minimum, so that thecooling of the same will be more easilyeffected, inasmuch as at a constant combustion-surface a favorablerelation between the cooling area and the iron mass to be cooled isrealized, while at the same time it becomes possible to providecooling-passages a2 in the grate-bars, and therefore nearer to the tire.In consequence of this arrangement the'sliding bars b are now protectedagainst excessive heating by being cooled from below by the cold air andat the upper parts bythe artificial cooling means of the step-bars,which latter are also efficaciously cooled by the air passingunhindered' through the recesses of the sliding bars b.

The cooling medium, which may be water or air or air mixed with atomizedwater, is conducted through a pipe c into the rear and lowest end of oneof the longitudinal branches A of the frame. These hollow longitudinalbranches are provided with crosspartitions d, so as to cause the coolingmedium to pass from the one longitudinal branch through the passage a2of one of the ste p-bars (or, if desired, through several bars) into theopposite longitudinal branch A, from here again through the nextfollowing group of step-bars back into the first longitudinal branch,and thus pass in the saine zigzag ourrent through the whole frame andout through the pipe c back into the reservoir from which it had beendrawn off The cooling medium is caused to flow in a direction oppositeto the draft in the furnace, and thus the coolest portion of it isbrought into contact with the hottest part of the grate, which itnaturally cools, more or less, according to the difference intemperature in the two. With the absorption of heat and consequentdilatation of the cooling medium the rising tendency of the latter isincreased, which causes a rapidv passage of the cooling medium from thereservoir through all the parts of the tire-grate, and thereby coolseffectually even the lessheated front bars of the grate.

The supporting-bars f of the movable grate Ahaving a to-andfro slidingmotion and at the same time an up-and-down motion are guided betweenguide bars on the longitudinal branches A and are supported by quadrantsf', mounted on shafts f2 and provided at their sides with toothedsectors f3, adapted to engage with the teeth of the bars f, and thuscause the motions of the grate b. When the sliding grate is in itslowest position, it will be balanced by a eounterweightf4 whereby butlittle power is required to move the sliding bars.

The hollow longitudinal branches A of the frame are adapted to tit, withtheir exterior walls, the circular form of the furnace-walls, where suchexist, as shown at Figs. 4 and 7. For boilers with verticalfurnace-walls (see Figs. 10 and 11) the longitudinal branches A are ofrectangular section.

In corrugated furnace-tubes, Figs. .tand 7, the spaces between thecorrugated walls and the or-anches A require to be filled in, so as notto impair the effectual working of the furnace. These spaces are closedby side flanges dx, which are entirely of solid material, and may bearranged on a level with the upper surface of the longitudinal branchesA, Figs. l and 4. It is, however, more advantageous to arrange thesedanges atan incline and so as to surpass in height the upper edges ofthe step-bars ct and of the sliding bars l), as shown in Fig. '7. Theseflanges may, as shown at Figs. b' and 7, be provided with openings, soas tocause an even combustion over the whole width of the grate.

The step-bars a in the arrangement represented at Figs. l to 7 areconnected to the side branches A by two screw-bolts s', (see Figs. 6 and7,) while only one such screwbolt s is required in the arrangementrepresented at Figs. 10 and 1l. These screws are easily removed whenrequired for the purpose of removing and renewing one of the stepbars.

The quadrant-piecesf' at the front and rear, or in some instances thoseat the front only, are rounded at the front part f4, Figs. 9 and 10, soas to enable them to be moved from the position shown in full lines tothat shown in dotted lines, and thus enabling the sliding bars to beremoved and also the screws s' to be loosened by a suitable Spanner.

. The sliding bars b of the movable grate in the furnace (shown at Figs.l and 2) are provided with rectangular openings as well as with recessesat the front edge. In some instances, however, they may only7 have thefirst-mentioned openings, and the edges surrounding these openings be ofan increased height, (see Fig. 2,) so as to prevent the sliding barsfrom becoming warped by the heat.

The fuel is supplied to the furnace from a hopper g, arranged in frontof the boiler above the grate. According to the arrangement shown inFig. 1 this hopper is provided with bottom g', inclined toward the rear.This bottom is adjustable by means of a weighted arm g2. A balancedvertical plate g3 at the rear of the hopper, together with the bottomg', enables the supply of combustible material to be regulated accordingto the ad- IOO IIO

vancing movement of the same on the furnacegrate. The movable andadjustable bottom g of the hopper g can also be arranged horizontally,as shown in Fig. la. In this case instead of the weighted lever anoscillating slitted lever g4 is provided, connected on one side with thebottoni g and on the other`side with the adjusting-lever g5. Thedisplacement of the lever g5 has for consequence also a displacement ofthe bottom g', whereby the feeding-aperture, and consequently also thesupply of the fuel, is regulated in any desired manner.

The described manner of adjustment-of the feeding-aperture within verylarge limits enables all sorts of solid fuel to be employed, such aswood-shavings, wood-dust, and cuttings, coal in its differentforms-viz., dust, rubble, nuts, and cobbles, as well as coke and peat.

The ashes and clinkers are removed and thrown into the ash-pit by meansof a sliding plate h, adapted to be moved by a lever h2 against theinclined edge 7L at the lower part of the fire-bridge, where theaccumulated ashes are caused to fall down into the pit by simply slidingthe plate h inward.

I claiml. In a horizontal water-bar grate, the coinbination with sidebars and serrated, rearward ly-inclined conn ecting-bars water-cooled,of a series of similarly-inclined pusher members, one between each pairof water-bars, each of said members provided with perforations ofsufficient length to never cut od draft through the grate, substantiallyas described.

2. In ahorizontalwater-bar grate, the combination with stationary sideand stationary rearwardly-inclined, serrated water-bars; of a series ofsimilarly-inclined balanced pusherbars coperating therewith andorganized to produce a movement of the fuel from front to rear of thegrate, each pusherbar provided with slots of a length greater than thelength of movement of said bars, substantially as and for the purposeset forth.

3. The combination with a fixed step-grate having inclined hollowgrate-bars provided with a toothed or comb-like web, and a sliding gratehaving grate-bars sliding between those of the fixed grate, thefaces ofsaid sliding grate-bars being at all points parallel with thecorresponding faces of the fixed grate-bars, said sliding bars havingslots in line with the interspaces in the co uib-like web of the fixedbars, said slots of such length as to prevent the movable bars, whatevertheir position relatively to the fixed bars, from covering the webinterspaces of the latter, for the purpose set forth. Y

4. In a horizontal water-bar grate, the combination with stationary sideand serrated,

rearwardly-inclined, connecting water-bars, means for causing a coolingmedium to circulate from the rear to the forward portion of said gratezigzag through the series of connecting water bars, a series of balancedpusher-bars coperating with the connecting water-bars, similarlyinclined and organized to move fuel from front to rear of said grate, afire-bridge and a dumping member between said fire bridge and grateorganized to deliver ash into the pit, substantially as set forth.

5. In a furnace, a horizontal water-bar grate, serrated,rearwardly-inclined, watercooled grate-bars, a series ofsimilarly-inclined pusher-bars coperating therewith, and a fuelfeed-hopper and a pair of slides angular to one another, andindependently adjustable to regulate the fuel-feed, substantially asdescribed.

6. In a furnace, a horizontal waterbar grate, comprising serrated,rearwardly-inclined, water-cooled grate-bars, a series ofsimilarly-inclined slotted pusher-bars coperating therewith, organizedto progressively move fuel from front to rear of the grate, eachpusher-bar provided with slots longer than the length of its motion; incombination with a fire-bridge and a sliding plate between said tirebridge and grate organized to drop ash into the pit, substantially asdescribed.

7. In a furnace, a horizontal grate, comprising a pair of longitudinal,and a series of rearwardlyinclined, serrated, connecting water-bars,means for circulating a cooling medium through the series of bars, aseries of slotted pusher-bars coperating with the water-bars, andsimilarly inclined, each of said pusher-bars having slots longer thanthe length of its motion, a lateral lug on each pusher-bar below thegrate and an actuating member engaging said lugs and common to all thepusher bars, substantially as described.

8. In furnaces having a fixed step-grate and a movable grate, thecombination of the toothed sectors f gearing with corresponding racks onthe movable grate-frame f, the shafts]02 mounted in hangers from the Xedgrate-frame A whose bars are bolted thereto, whereby the slidinggrate-bars may be removed from between the fixed grate-bars to affordready access to the bolts and facilitate the removal of any one of thefixed grate-bars, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

FRITZ FRANZ MAIER.

Witnesses HARRY BELMONT, DAVID ALRIN.

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